The invention pertains generally to process tubes used in semiconductor manufacturing.
A process tube is a device that is used in the manufacturing of semiconductor wafers. These tubes are inside furnaces that reach temperatures of up to 1200° C. Whenever the wafers are taken out of the tubes, the tubes are considered to be at idle. An exhaust system, known as a Scavenger, is attached to the furnace to remove the gasses used in the processing of the wafers. When the process tubes are at idle, ambient air is sucked into the openings of the process tubes and tends to overload the exhaust system. Particles and contaminants are also able to flow into the process tubes, which can lead to the contamination of the wafers during processing. There is also a large quantity of heat radiating from the process tubes due to the high temperatures generated by the furnaces. This can be an unsafe condition for the operator, adversely raises the room temperature, and increase the time it takes for the wafer boat to cool down. It also reduces the additional build-up of an oxide layer on the semiconductor wafer.
It is not uncommon for operators to use a make-shift cover to temporary close the process tube by manually lifting and placing a rigid sheet of metal across the opening to close it, and then removing it for insertion of wafers. One problem with this approach is that the cover can be dropped or knocked against the wafers, potentially damaging many thousands of dollars worth of wafers.